You've probably seen the "blue-and-orange" thing in movie posters. It makes sense, they are sharp contrasting colours, visually striking but still warm, stylish, and easy on the eye (unlike the neon magenta and glow-in-the-dark-green combo), so why not embrace this little visual trick and hack away.

But they aren't the only trick in the book. There are a few elemets that have been appearing in movie posters for a while, and they are usually genre-specific and say a thing or two about the movie itself (whether they mean to or not).